I. Field of the Invention
The present invention relates to improved and less costly techniques for molding jewelry during mass production. More specifically, the present invention relates to the manufacture and use of low cost silicone molding compounds within a hard aluminum injection mold frame. Use of such apparatus streamlines the molding and injecting of multiple jewelry patterns as compared to the lost wax method of casting jewelry components.
II. Description of the Prior Art
Today there exists a variety of techniques for manufacturing jewelry such as rings, pendants or the like. The lost wax manufacturing process starts with an original model. The model is typical of a one-of-a-kind item made from a variety of materials. This model has a mold made around it and is removed from the mold to create a hollow cavity. An air, hydraulic wax or plastic injector is then utilized to force wax or plastic into the mold cavity. Multiple injected wax patterns from this mold allow many of the same item to be reproduced. Each model requires its own mold for production.
The construction of molds used in the lost wax or other manufacturing processes is time-consuming and expensive. Several molding materials are utilized for a variety of manufacturing processes. Silicone rubber, gum rubber and a lead-type metal are industry standards for mold-making materials. Each model requires an individual mold for production. As the designs grow more detailed, the tooling required to make the mold becomes more intricate and the cost of the mold increases. A single mold may cost several hundred dollars and can be made in many multiple pieces.
Over time and as a result of use, these molds do wear out. Lead-type molds oxidize. Because the molds wear out, all master models must be retained so that replacement molds can periodically be created. Making molds of metal have other serious draw backs. For example, such molds are very rigid and typically are made to split in two along a single rigid parting line. This limits the sophistication, intricacy and dimension of the design that can be created. It also limits the nature of true dimensional design (models with severe undercuts, for example). In addition, metal molds have a shrinkage factor when used as a molding material. This creates the need for an additional factor to be incorporated into the model-making process to compensate for wax pattern consistency. Fitting stones into the model and taking the model through the mold-making process makes additional tolerances for stone sizing necessary. Finally, metal molds made of a lead-type material pose significant health concerns.